Silylalkyl phenylthiolates

ABSTRACT

THIOLBENZOIC ACID IS ADDED TO ALKENYLSILANES OR SILOXANES TO GIVE COMPOUNDS OF THE FORMULA PHENYL-CO-S-R-SI(-R&#39;&#39;)N(-X)M-O 4-N-M/2 FOR EXAMPLE, THIOLBENXOIC ACID IS ADDED TO VINYLDIMETHYLCHLOROSILANE UNDER THE INFLUENCE OF ULTRAVIOLET LIGHT TO GIVE C6H5C=OS(CH2)2SI(CH3)SCL. THE THIOLATES ARE USEFUL AS INTERMEDIATES IN THE PREPARATION OF MERCAPTOALKYLSILANES AND SILOXANES.

United States Patent 3,661,954 SILYLALKYL PHENYLTHIOLATES Gary E. LeGrow, Midland, Mich., assignor to Dow Corning Corporation, Midland, Mich. No Drawing. Filed July 13, 1970, Ser. No. 54,666 Int. Cl. C07f 7/10, 4/18 US. Cl. 260448.2 N 4 Claims ABSTRACT OF THE DISCLOSURE Thiolbenzoic acid is added to alkenylsilanes or siloxanes to give compounds of the formula CtH C=OSRSiR'nXmO T For example, thiolbenzoic acid is added to vinyldimethylchlorosilane under the influence of ultraviolet light to give C H C''OS(CH Si(CH- Cl. The thiolates are useful as intermediates in the preparation of mercaptoalkylsilanes and siloxanes.

Mercaptoalkylsilanes and siloxanes are well known materials and have found wide utility. They are used, for example, to increase the adhesion of vinylic polymers to siliceous substrates, as lubrication additives and as modifiers for organic plastic materials. Applicant has found that these desirable mercaptoalkylsilanes can be prepared by reacting the compositions of this invention with amonia as will be described in more detail hereafter. The instant thiolates can be used to prepare mercaptoalkyl silanes and siloxanes in which the mercaptoalkyl group is of any chain length. The materials of this invention are particularly desirable starting materials for the preparation of a fi-mercaptoethylsilanes and siloxanes.

This invention relates to compounds of the formula in which R is an alkylene radical of at least 2 carbon atoms, R is a monovalent hydrocarbon or halohydrocarbon radical free of aliphatic unsaturation, X is halogen, alkoxy, carboxyacyl, ketoxime, amineoxy or OH, X being free of aliphatic unsaturation, n is 0 to 2, m is 0 to 3, and the sum of n+m being no greater than 3.

This invention further relates to copolymeric siloxanes having at least one siloxane unit of the formula in which R, R and X are as above defined, n and m each have values from 0 to 2, any remaining siloxane units being of the formula It",si0

in which R" is an R group or an X group, and a is an integer from O to 3 inclusive.

The compositions of this invention are best prepared by adding thiolbenzoic acid to the corresponding alkenylsilane or siloxane under the influence of a free radical generator such as peroxides such as benzoyl peroxide; azo-bis-nitriles such as azo-bis-isobutyronitrile or radiant energy such as ultraviolet light, X-rays or gamma-rays. The temperature of the addition is not critical and temperatures from 30 to 100 C. are suflicient.

For the purpose of this invention R can be any alkylene radical of at least 2 carbon atoms such as dimethylene, trimethylene, tetra-methylene or octadecainethylene. R can be either straight chain or branched in structure.

R can be any monovalent hydrocarbon radical or halohydrocarbon radical free of aliphatic unsaturation such 3,661,954 Patented May 9, 1972 ICC as alkyl radicals such as methyl, ethyl, isopropyl or octadecyl; cycloaliphatic hydrocarbons radicals such as cyclopentyl, cyclohexyl or methylcyclohexyl; aromatic hydrocarbon radicals such as phenyl, xenyl, naphthyl, anthracyl, tolyl or xylyl; aralkyl hydrocarbon radicals such as benzyl, fi-phenylethyl or B-phenylpropyl. R can also be any halogenated monovalent hydrocarbon radical such as chloromethyl, gamma-chloropropyl, dibromophenyl, 3,3, 3-trifluoropropyl, bromo-cyclohexyl, chlorophenyl, a,oz,octrifluorotolyl or iodophenyl.

X can be various types of hydrolyzable radicals such as the alkoxy 1 radical such as methoxy, ethoxy, isopropoxy, octadecyloxy, fi-methoxyethoxy, fi-ethoxyethoxy, -(OCH CH OCH OCH CH(CH )OC H fl-hydroxyethoxy or B-hydroxyisopropoxy. X can also be any carboxyacyl radical such as formoyl, acetyl, propionyl, benzoyl, cyclohexoyl or stearoyl. X can also be any ketoxime radical of the formulae -ON=CB or in which B is any hydrocarbon radical such as methyl, ethyl, octadecyl, phenyl, cyclohexyl or benzyl, and B is divalent hydrocarbon radical such as trimethylene or hexamethylene. X can also be any amineoxy radical of the formula B NO- in which B is any of the monovalent hydrocarbon radicals shown above.

As can be seen the compositions of this invention can be silanes or siloxanes. The siloxanes can be homopolymeric or they can be copolymeric in which each of the silicons has one of the phenylthiolate groups attached thereto. Also the compositions of this invention can be copolymers of siloxanes in which at least one unit has a phenylthiolate group attached to the silicon and the remaining siloxane units are of the formula in which R" can be any of the radicals shown above for X and for R. It can be seen therefore that the copolymers can contain units of the formulae SiO R"SiO' R" SiO and R" SiO It can also be seen that when D represents the radical C H C=OSR, the siloxanes of this invention can contain units of the formulae DSiO DR'SiO, DRgSiOj, DXSiO, DX SiQ and DR'XSiO In any copolymer the units can vary with respect to the type of D group or the type and/ or number of R and X groups.

The composition of this invention can be converted to the corresponding mercaptans by reacting them with gaseous ammonia. Reaction takes place rapidly by merely passing the gaseous ammonia through the phenylthiolate at temperatures of C. In general, an exothermic reaction occurs With the formation of the corresponding mercaptan and the byproduct benzamide.

The following examples are illustrative only and should not be construed as limiting the invention which is properly delineated in the appended claims. The following abbreviations are used infra, Vi for vinyl, Me for methyl, Et for ethyl and Ph for phenyl.

EXAMPLE 1 A mixture of 264 g. of vinylmethyldimethoxysilane, 138 g. of thiolbenzoic acid and a catalytic amount of azobis-isobutyronitrile was irradiated in quartz glassware for 69 hours with stirring. The irradiation was done with ultraviolet light. Investigation of the product by nuclear 1 The term alkoxy includes allroxyalkoxy radicals and hydroxyalkoxy radicals.

magnetic resonance showed it to be the compound of the formula (MeO) MeSiCH CH- 'SO=CPh.

EXAMPLEZ A mixture of 296 g. of vinyltrimethoxysilane contain- 4 EXAMPLE 6 When the following silanes are reacted with thiolbenzoic acid in accordance with the procedure of Example 1, the following products are obtained. Z is the group ing a catalytic amount of azo-bis-isobutyronitrile was 5 PhC=OS--.

ViSiCoHu CH2 CHzOMe) 2--.-

\'iSi(CuH3BI')z (0M8):

v suctmctnari .II- zwnazsuctmctnar, VlSKPhz) OH Z(CH1)zSiPh1OH CHz=CH(CHz)1eSi(OEt)z(OOCH) zwmmsuonmoocn heated at 60 C. as 138.2 g. of thiolbenzoic acid was added over a period of one hour. The solution was then heated 20 hours at 70 C. The product was then irradiated for 71 hours in quartz glassware with ultraviolet light.

EXAMPLE 7 When the following siloxanes are reacted with thiolbenzoic acid in accordance with the procedure of Exam- The residue was strip distilled to give the product 25 ple 5, the following products are obtained. All percents (MeO) SiCH CH SO=OPh. are mol percent. Z is the PhC "OS- group.

Siloxane Product (ViMezSlOhSi Z(CH2)2M92S10)4S1 CH2 CHOHzSl(Osl(Ph)20H)3 Z(OHz)aSl(0Si(Ph)2OH)a CH =C (Me) CH2 SiMmOSiMez (ClaHav) ZCHzCH(Me)CH1SiMezOSlMe1(C1 H;1)

% ViSiO 5% Z(CH2)2SiO3/z P115103]; 10% PhSlOa/g CtHuSiOa/z 25% CaHuSlOa/t (McCrHQMeSiO 40% (MeCsHOMeSlO 20% (ClCaHQMeSlO 20% (CICuHOMeSlO 20% VlSl(CH2CHzCFa)O 20% Z(CH2)2S1(CH2CH2CF3)O 20% (CF CuH4)MeSiO 20% (CFzCaHOMeSlO 59% (CF3CH2CHz)MeSiO 59% (CFaCHzCHDMt-BSlO 1% (CF3CHZCH2)MOZSiO.5 1% (CFaCHnCH2)Me:S1O.5

10% Vi(MeO)2SlO 5 10% ZCH:CHz(MeO) SiO.5 20% Cl(OH2)sMeS1 20% Cl(CH2)aMeSiO 20% (PhCHCzH2)MeSlO 20% (PhCHzCHflMGSlO BICeHflMQSiQ 50% BrCsHKMe) S10 CH2=CH(CHz)m lM820-5 Z CHz ra iMiz04 EXAMPLE 3 That which is claimed is:

A stirred mixture of 55.3 g. of thiolbenzoic acid, 48.3 g. of vinyldimethylchlorosilane and a catalytic amount of azo-bis-isobutyronitrile was irradiated with light of 2537 A. wavelength for 26 hours. There was obtained the product PhC=OS(CH SiMe Cl having the following properties: B.P. 129 C. at .1 mm., n 1.5535 and d 1.1055. No a adduct was found.

EXAMPLE 4 This example illustrates the preparation of a mercaptoalkylsilane.

An excess of ammonia was blown into ('MeO) MeSiCH CH SO=CPh for two hours at 50 C. The liquid product was separated from the benzamide byproduct and was found to be HSCH CH Si-Me (OMe EXAMPLE 5 1. A compound of the formula CuH C=OSRSiR' XmO3- -m in which R is an alkylene radical of from 2 to 18 carbon atoms,

R is a monovalent hydrocarbon or halohydrocarbon radical free of aliphatic unsaturation, X is halogen, alkoxy, carboxyacyl, ketoxime, amine oxy or OH, X being free of aliphatic unsaturation,

R and X containing no more than 18 carbon atoms,

n has a value from 0 to 2,

m has a value from 0 to 3, and the sum of n+m being not greater than 3.

2. The compound of claim 1 in which R is R is methyl, X is chlorine and the sum of n+m equals 3.

3. The compound of claim 2 in which n is 2 and m is 1.

4. A copolymeric siloxane having at least one unit of the formula in which R is an alkylene radical of from 2 to 18 carbon atoms,

6 R is a monovalent hydrocarbon or halohydrocanbon References Cited radical free Of aliphatic unsaturation, P X is halogen, alkoxy, carboxyacyl, ketoxime, amineoxy or hydroxyl, X being free of aliphatic unsaturation, 2544396 3/1951 Burkhard 260-4481 N R and X containing no more than 18 carbon atoms, 5 2,802,853 8/1957 George 2604482 N n has a value from 0 to 2 2,863,898 12/ 1958 Merker 260448.2 N m has a value from 0 to 2, and the sum of 3,445,496 5/1969 Ryan 260448'8 R n+m being not greater than 2, I any remaining siloxane units being of the formula TUBI'AS LEVOW Pnmary Exammer RHnSiOH 10 P. F. SHAVER, Assistant Examiner 2 US. '01. X.'R.

in which R" is an R group or an X group and a has a value from 0 to 3 inclusive.

260-465 E, 399, 448.2 B, 448.8 R 

